Reaction of electrogenerated [CoI(salen)]– with t-butyl bromide and t-butyl chloride

Abstract

The compound [Co^I(salen)]^–[salen =NN′-ethylenebis(salicylideneiminate)] electrogenerate in the presence of Bu^tX (X = Cl or Br) yields [Co^II(salen)] and organic products. With Bu^tBr the reaction takes place in two steps, the rates of which have been determined. The first step leads to rapid disappearance of [Co^I(salen)]^– by a second-order reaction and has been studied by cyclic voltammetry. The second step is the slower regeneration of [Co^II(salen)]. When [Co^II(salen)] is reduced to [Co^I(salen)]^– in the presence of Bu^tBr an overall electrocatalytic process ensues which has been studied by controlled-potential reduction and polarography. All evidence is consistent with the formation of an unstable organometallic intermediate which decomposes into [Co^II(salen)]. 2-Methylpropene and hydrogen are the main products arising from the butyl radical.